For more than a century, Seattle’s economy has cycled through booms and busts, and the latest upturn is poised to unfold on the waterfront.

That’s where the city’s first big boom began in 1897, when the steamer Portland docked and discharged Klondike miners laden with gold. Today’s prospectors are looking not for precious metals but waterfront property that in five years will be transformed with demolition of the Alaskan Way Viaduct and development of a new promenade along the shore.

Eager investors are scouring the neighborhood for properties, but finding willing sellers is proving to be as elusive as unearthing the mother lode.

The owners are holding on to their property, hoping that property values will increase in the years leading up to the removal of the noisy viaduct, which is scheduled to come down in 2016 after the two-mile-long, $2 billion tunnel that will replace it opens.

It’s difficult to find evidence that property values are rising today, said Peter Shorett, an appraiser with real estate services company Kidder Mathews. However, as viaduct demolition nears, the value of every property within two blocks of the viaduct should increase, he said.

That would be good news for property owners and the city, which plans to fund part of the new waterfront park with a Local Improvement District.

Real estate investors such as Jeff Schoenfeld of Seattle are already looking for opportunities with the once-in-a-lifetime change on the horizon.

That’s why he bought the Boston Hotel at 76 S. Main St. He acquired it in May at a courthouse sale for just under $1.1 million, or about $700,000 less than what the property sold for in 2008.

Schoenfeld said he bought the three-story building as a long-term hold. He’s going to explore turning the building into retail or restaurant space. Today, there are three apartments, a law office and the office of Schoenfeld’s company, J-Max Real Estate, in the building.

Schoenfeld is getting about $1.80 per square foot in rent for apartments that are mere feet from the viaduct. He was hoping to get $2 a square foot after putting in new hardwood floors and stainless steel appliances, but that isn’t realistic when you have “a viaduct staring you in the face,” said Schoenfeld. He thinks he’ll be able to get more than $3 a foot by 2020, and said $3.60 a foot “is not out of the realm of possibility.”

Today, developers of new downtown apartments aim to get $3 a square foot.

There are many old buildings along the waterfront that are ripe for repositioning, like the Boston Hotel. It’s more difficult to find redevelopment sites.

Real estate broker Tom Graff of Ewing & Clark has been looking. “I’ve not been able to pry loose any properties on Alaskan Way,” he said.

What he has found is more opportunity in the West Edge, the downtown neighborhood just east of the waterfront. There he found seven potential redevelopment sites now occupied by surface parking lots and low-slung buildings.

One of those sites is at the northeast corner of Alaskan Way and University Street. It’s there that multifamily developer Harbor Urban has told the city it may build a 16-story tower. Harbor Urban officials declined to comment on the one-third acre parking lot that it does not yet own.

One of the most enticing sites is owned by Myrtle Woldson. The 102-year-old resident of Spokane eight years ago bought the surface-parking lot at Alaskan Way and Spring Street for just over $2.75 million.

Shorett, of Kidder Mathews, said the lot, which measures more than three-fourths of an acre, is “just a cash cow right now. It generates so much revenue for parking.”